Her son and his friend Takanobu are nearing the end of their school entrance exams. Reiko gently encourages and supports them. Takanobu has a crush on Reiko, and one day, he asks her to go on a date if he passes the exam. Reiko accepts, happy that she is seen as a woman. After passing the exam, Takanobu and Reiko go on a date in secret from her son, but he also desires her body, and they end up in a forbidden relationship. However, after experiencing the pleasure of a young penis, Reiko finds it difficult to refuse Takanobu's advances...